There are two cars which received the top ACEEE Green Score of 54 thanks to low related carbon and tailpipe emissions.  However, due to limited access to refueling/recharging options and limited sales availability, they are not on TopTen's primary list.  

These two highly environmentally-friendly models are the natural-gas-powered Honda Civic GX and the all-electric Nissan Leaf.  Depending on where you live and how you use your vehicle, these low-emission options might be right for you.

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